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An additional menu should be available to manage discounts.

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To Create a new Discount and press ‘Add New’ Fill Title:

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Custom fields should be filled.
discount Discount - the amount of discount (Required for all).
One of discount type date, time, dayofweek.

And Press ‘Publish’.

Test plugin

Select desired data and you should see Discount % on available time Discount % is added to the Comments field for reservation

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